Given that both the solar magnetic field and the solar irradiance has been continuously sampled with space-based instruments for almost an entire 22-year solar cycle, what is the relation between these two observables and what conclusions can be drawn from such relations?
Plenary speaker: Kok Leng Yeo (MPS)
|17:00||Solar irradiance variability and surface magnetism||Yeo, K||Invited Oral|
| ||Kok Leng Yeo, Sami Solanki, Natalie Krivova|
| ||Max Planck Institute for Solar System Research|
| ||The variation in solar irradiance is commonly assumed to be driven by its surface magnetism. Until recently, this assumption could not be verified conclusively as models of solar irradiance variability based on solar surface magnetism have to be calibrated to solar irradiance measurements. Making use of realistic three-dimensional magnetohydrodynamic simulations of the solar atmosphere and state-of-the-art full-disk magnetograms from SDO, we developed a model of total solar irradiance (TSI) that does not require any such calibration. The modelled TSI variability is therefore, unlike preceding models, independent of TSI measurements. The model replicates over 95% of the observed variability over the lifetime of SDO, confirming the relationship to solar surface magnetism and leaving limited scope for alternative drivers of solar irradiance variability (at least over the time scales examined, that is, days to the solar cycle).|
|17:30||The GOES EUVS Model: New Operational Spectral Irradiances from GOES-R ||Thiemann, E||Oral|
| ||Edward M.B. Thiemann, Francis G. Eparvier, Thomas N. Woods, Andrew R. Jones, Martin Snow, Donald L. Woodraska, Janet Machol|
| ||(1) Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, USA (email@example.com), (2) NOAA Space Weather Predictions Center, Boulder, USA|
| ||In order to monitor solar EUV variability, NOAA has included the EUVS Model, an operational (continuous, high time cadence, low latency) EUV irradiance data product as part of its Geostationary Operational Environmental Satellites (GOES) -R series program. The GOES-R satellites are planned to make observations from 2016-2035, providing nearly two decades of real-time continuous EUV irradiance data, and changing the paradigm for the availability and dissemination of spectral EUV irradiance data.
The GOES EUVS Model is an operational, real-time, coarse-resolution EUV spectrum which is derived from the 10 calibrated irradiance measurements of the GOES EXIS instruments. The EUVS Model is based on measurements from SORCE/SOLSTICE, TIMED/SEE and SDO/EVE. In particular, the high time cadence measurements from SDO/EVE are used to calibrate the long-term variability from 6-35 nm and short-term variability from 6-106 nm. The model has a 30 second latency and cadence, and spans the wavelength range from 5 nm to 127 nm. Between 5 and 115 nm, the model spectral resolution is 5 nm, and there is a single 10 nm wide bin from 117-127 nm. The model uses the best available measurements to estimate the irradiance in each model bin, and a spectrum can be produced as long as any one of the EUVS channels (A, B or C) are available. The EXIS model decomposes the EUV irradiance into short and long time-scales, specifically, a daily average and some contribution to the daily value at a 30 second cadence. We show that the model uncertainty for daily average irradiances ranges from 1.6 to 5.4 % for the model bins and that model predictions of M-class or greater flares is typically less than 20% for all bins except the 10-15 nm and 95-100 nm bins, which have uncertainties of 68% and 31.8%, respectively.
|17:45||Kinetic and Current Helicity of Long-Lived Activity Complexes During Solar Cycle 24||Komm, R||Oral|
| ||Rudolf Komm, Sanjay Gosain|
| ||National Solar Observatory, Boulder, CO 80303|
| ||We study long-lived activity complexes during Solar Cycle 24. We focus on the kinetic helicity below the surface determined with ring-diagram analysis applied to full-disk Dopplergrams from SDO/HMI. In addition, we study the current helicity at the solar surface of these activity complexes determined from synoptic vector magnetograms. Current and kinetic helicity of activity complexes follow the hemispheric helicity rule with mainly positive values in the southern hemisphere and negative ones in the northern hemisphere. The locations with the dominant sign of kinetic helicity are more organized than those of secondary sign even if they are not part of an activity complex, while locations with the secondary sign are more fragmented. We will present the latest results.|